Photoluminescent‐Electrochromic Synergy in Passive Devices for Pressure Visualization and Multi‐Level Encryption

Abstract A novel self‐powered opto‐electrically coupled non‐pixelated electrochromic device has been presented for dynamic pressure visualization, addressing the limitations of conventional pressure sensors, such as rigid systems, high power consumption, and environmental sensitivity. The device integrates a flexible architecture with a WO ₃ @Eu ³ ⁺/Ag nanowires (Ag NWs) composite layer, enabling dual‐mode pressure‐responsive optical modulation: electrochromism under mechanical pressure and photoluminescence for dark‐environment visualization. By leveraging the redox potential difference between, and liquid metal (InSnBi) electrodes, the device achieves self‐powered color switching without external energy input. An air gap design isolates the electrolyte and electrochromic layers, ensuring localized pressure‐triggered color changes. Experimental results demonstrate a high spatial resolution (200 µm), a broad pressure response range (0–25 N), and stable pattern retention for 30 days. The dual‐mode operation, combining pressure‐induced electrochromism and rare‐earth photoluminescence, enables applications in biometric authentication, dynamic art preservation, and multilevel optical encryption. This work advances flexible sensing technology by merging mechanical and optical biometric features, offering a low‐power, environmentally adaptable solution for real‐time pressure visualization.